Every time I take the truck through some muddy puddles I always end up with oxygen sensors that do not want to alternate up and down. They all start at a normal value .45V and then they go to like 1.2V and then down to some value, around .3V up front and .8V in the back, triggering lean codes and ends up dumping gas. They move about .08 up and down at the most but are really just pretty steady. Both banks have the issue, although the passenger bank just started working again. They randomly come back online and start showing alternating values whenever they want. One time I went splashing in January and the truck wasn't happy again for 3 months no matter what I did, and most recently I went like 3 days ago and the passenger side just started working, still got driver side issues. Something must be getting wet that shouldn't be but what?

Everything has to be dried out by now, especially considering I just drove it for 2 hours.

O2 sensors are less then a year old. No vacuum leaks. I spent months checking everything mechanical.

Only thing I can think is the ECU or BCU and I just tore apart the glove box and the BCU and ECU are clean and dry. I daily drive with this truck so the ****ty gas mileage really hurts but I don't want to give up going offroad. I don't think the wiring could be bad because they are reading values.

Any ideas?

 

few things could throw off readings

water mud dirt bad wiring on connectors etc
fuel purge valve if failing or stuck open can cause havoc
wet maf or vaccum leaks. You need a smoke machine to get the vaccum lines properly tested

 

I did a whole thing with the smoke machine 2 months ago when I had this same problem from the same cause. I replaced my exhaust manifold and rewelded my entire y-pipe to fix any and all exhaust leaks. Swapped o2 sensors side to side, no change. MAF sensor was reading correctly and moving correctly according to other reported values on the forum. I don't think it is bad wiring to the sensors because I don't think they would be reading at all if that was the case, and to further prove it it is either an entire bank or nothing, that is why I was leaning towards the computers. Anyway when I did the smoke machine and found no leaks, I went and started it to move it and it just randomly started working.

I do get an occasional P0441 error but I tried changing the purge valve already and no change. Unless you are referring to a different one.

 

Unplugging, letting sit for a few hours, and replugging the ECU seems to have done fixed it. For how cheap they are I might just get the set of 3 bcu ecu instrument cluster, with close enough miles and replace them all.

has anyone replaced the 02 sensor wires and are they apart of the main engine wire harness? I haven’t really done any research but just any pointers to it

ill check the rave as well when I get a chance

 

sounds like you have done some leg work
if I remember correctly I replaced my front O2 sensor plugs with my rear O2 sensor plug.
I cut the O2 sensor wires from harness attached them to a plug from a rear O2 sensor and plugs right in to the front plug.
Ill dig up a pic I took when I had this issue. Of the plug

 

Look at the wires where they go into the plug they were failing. That’s from harness to o2 plug.

 

Once water enters the 02 connection, it has a harder time getting out. Pressure and the force of moving water penetrates the connection, and once it's in there...it doesn't have those same conditions to release it from inside the "water tight" plug. So, in essence...it could stay in there for a long time. Clean 02 plugs and apply electrical plug sealant.

 

So you’re saying that the front sensors should plug into the rear sensors, so I can cut the plug off old rear sensors and replace the truck plug in the front. Sounds good I’ll take a look at that.

maybe even just splice them and solder them together, I’m pretty good at that after owning a boat in salt water for a few years, lol

 

makes a lot of sense. I don’t really know of any or about electrical plug sealant, could you recommend some?

I’d assume it’s some rtv type stuff but everyone has their opinion about what’s the best. Experience is everything..

Thanks

 

yup that’s what I did